Lack of volume control
550 pairs lovely with carda spirit hd.BUT. Absolutely no control off volume. Tom tom manual states it is the headset that controls the volume. This just does not work. Disconnect head set then you adjust tom tom volume by the slider bar.BUT as soon as you reconnect headset it defaults to max, which is not only deafening but will eventually destroy the speakers. Sort this out tom tom. RIDER 550, I DONT THINK SO.